a hydraulic, physical representation designed by Bill Phillips in the 1920s that simulates the macroeconomic flow of money in a national economy (moniac = Monetary National Income Automatic Computer). water is pumped into the top of the machine & then filtered down though a central column & then through pipes & chambers. the amount of money is represented by how much water is in a tank. the net flow of the system gathers at the bottom & is pumped back to the top to restart the cycle. different variables can be changed by tuning valves & other piping. [ & |via ]